Switches



mmmz May 14, 1957 Filed Nov. 6, 1952 W. H. HOLLINSHEAD SWITCHES 2Shets-Sheet 1 IN VENTOR BY SZ WQmQu% ATTORNEY May 14, 1957 Filed Nov. 6,1952 w. H. HOLLINSHEAD 2,792,467

SWITCHES 2 Sheets-Sheet 2 103 6K 63 I 1 3 (515 I ATTORNEY United StatesPatent 1 2,792,467 SWITCHES William H. Hollinshead, St. Paul, Minn.,assignor to Control Manufacturing Company, St. Paul, Minn., apartnership Application November 6, 1952, Serial N 0. 319,148 6 Claims.(Cl. 209-84) This invention relates to an improvement in switches anddeals particularly with a simple circuit switch designed for operationupon changes in liquid level.

Switches are often required for closing a circuit when a predeterminedliquid level is reached. These switches have to be extremely dependablein their operation and at the same time must be simple in constructionso that they may be low in cost. The present invention resides in theprovision of a switch which will accomplish these requirements.

A feature of the present invention resides in the novel manner in whichthe various parts of the switch are mounted. The switch contacts aremounted upon a panel of insulation provided with projections at oppositeends thereof. These projections spring into a U-shaped frame which inturn is supported within the relatively rigid outer housing. Whencontained within the housing 'the walls of the U-shaped support can notspread apart sufficiently to disengage the supported insulation panel.

A further feature of the present invention resides in the particularform of toggle arrangement which controls the contact blades. Thecontact blades are provided with aligned downwardly projecting ears. Anangularly shaped toggle lever which acts in the manner of a bell cranklever is provided with an upwardly directed extremity. An insulationmember is interposed between the upwardly directed arm of the togglelever and the downwardly projecting ears of the contact blades. Bypivotal movement of the bell crank type of lever the grooved member maybe swung into and out of alignment with the upwardly directed end of thebell crank lever, thereby urging the contact blades into and out ofcontact.

A further feature of the present invention resides in a switch whichembodies'elements which comprise a toggle unit and in which one of thetoggle levers comprises a block of insulation which is grooved toaccommodate retaining 'members on the contacts and on the other togglelever.

This block of insulation may thus be'operated to urge the switchcontacts into and out of circuit closing position. An added feature ofthe present invention lies in the provision of a toggle unit of the typedescribed above in which the block of insulation is provided withprojections which extend between the contacts engaged and is held fromlateral movement thereby. Thus the block. of insulation is held in placeregardless of the positions of the contact blades or of the other togglelever.

An added feature of the present invention lies in the manner in whichthe spring urging the switch contacts into one extreme position isadjusted. The helical tension spring is connected at one end to theswitch operating lever and extends into a tubular casing at its otherend. A screw extends into the tubular member and is threaded into thespring. By engaging the head of the screw with the opposite end of thetubular member from that containing the spring the tension upon thespring can be adjusted by rotating the screw in one direction or theother.

An added feature of the present invention resides in the provision of aswitch which is controlled by one or more weights which are denser thanthe liquid into which they extend. These weights always exert a downwardforce upon the operating lever, but the immersion of the weights in theliquid decreases the downward pull upon the operating leversufl'iciently to permit the lever biasing spring'to actuate the switchcontacts. l

2,792,467 Patented May 14, 15557 p ce the position of the view beingindicated by the line 4-4 of Figure 3.

Figure 5 is a sectional view through the switch, the position of thesection being indicated by the line 5--5 of Figure 2.

Figure 6 is a sectional view through the switch, the

' position of the section being indicated by the line 6--6 of Figure 2.

Figure 7 is a bottom plan view of the insulation platform which supportsthe contact plates.

Figure 8 is a perspective view of the toggle member which actuates thecontact plates. 7 Figure 9 is a perspective view of one of the membersforming a part of the toggle lever structure.

Figure 10 is a perspective view of the operating lever.

Figure 11 is a perspective view of the shell in which the operatingmechanism is mounted.

Figure 12 is a perspective view of the switch lever sup porting frame.

The switch is indicated in general by the letter A and is shown as itappears when closed in Figure 1 of the drawings. The switch A isactuated by means of an operating lever 10 which projects from the casein a manner which will be later described. A chain or other flexiblemember 11 is connected to the operating lever 16 and supports a pair ofweights 12 and 13 which are usually identical in form.

The weights 12 and 13 are supported at the desired elevation by suitablemeans such as a spring ring 14 which is placed through the chain tolimit the downward movement of the weights. The weights are providedwith apertures 15 and 16 extending therethrough for accommodation of thechain 11. The spring rings 14 thus may serve to adjust the elevation ofthe chains, one of which may remain immersed in the liquid and the otherof which may be above the normal liquid level line.

-In the particular embodiment illustrated the switch is designed to beopened by the weights 12 and 13 when the liquid level drops sufiicientlyso that the weight above the water overcomes the force of the leverbiasing spring which will be later described. Such an arrangement isdesigned for use, for example in conjunction with sump pumps which aredesigned to pump out liquid from the sump when a certain amountaccumulates therein. When the level of liquid raises sufioiently tolessen the downward force upon the operating lever below that of theswitch lever biasing spring, the lever is actuated to close the contactsand close the circuit to the sump pump or other device.

The weights 12 and 13 are provided with a substantially flat lower end17 and a slightly tapering lower body portion H which extends somewhatmore than half the height of the weight. The weights are provided with aslightly tapering portion 2t: which tapers upwardly and inwardly and afrusto-coni al upper portion 21. This shape of weight has been foundextremely effective for its prescribed purpose. The weights are moldedfrom any suitable material such as hard rubber or the like.

The operating mechanism of the switch is mounted within a substantiallyU-shaped support 22 which forms the bottom of the switch housing. Thesupport 22 includes a bottom panel 23 and parallel upwardly extendingside panels 24 and 25. A front flange 26 extends upwardly from theforward edge of the bottom panel 23 and is drilled at 27 to accommodatea metal screw or is threaded to accommodate a machine screw designed tohold the cover plate to the support to form the complete switch housing.

A pair of elongated slots 29 and 30 are provided in the end walls 24 and25 near the upper extremity thereof. For the purpose of simplicity instripping the stock from these slots 29 and 36, the slots may beT-shaped in form as illustrated with a connecting notch 31 or 32extending from the transverse notch to the top of the corresponding endwall. 7 a

An insulation platform 33 is supported between the end walls 24 and 25.As indicated in Figures 4 and 7 of the drawings this insulation block 33is provided with a pair of oppositely directed projections 34 and 35 ofproper size and shape to fit snugly into the slots 29 and 30respectively. Thus by merely springing the end walls 24 and 25 outwardlyand slipping the insulation platform 33 between these end walls, theprojections willenter their respective slots and hold the platformsuspended above the bottom panel 23 as shown in the various figures ofthe drawings.

A switch lever supporting frame 36 is mounted upon the bottom panel 23of the support 22. This frame 36 is U-shaped in section including abottom panel 37 shown in Figures 4 and 6 of the drawings and upwardlyextending similar side walls 39 and 40 extending upwardly in parallelrelation from opposite sides thereof. The bot tom panel 37 is providedwith integral ears 41 at opposite ends of the end wall which areprovided with threaded apertures to accommodate mounting screws 42. Themounting screws 42 extend through the bottom panel 23 of the switchhousing and into the ears 41 to hold the bottom panel 37 flush upon thebottom wall 23.

The parallel walls 39 and 40 are provided with irregularly shapednotches 43 intermediate the ends thereof. These notches includedownwardly and inwardly inclined portions 44 which adjoin outwardly anddownwardly inclined portions 45. From a fulcrum point of greatest widthindicated at 46, the notches extend downwardly and inwardly as indicatedat 47. Thus the notches form which cause the operation of the apparatus.

The operating lever is illustrated in detail in Figure 10 of thedrawings. This lever 19 includes an elongated arm 49 which is ofinverted channel shaped construction, the longitudinal edges of the armbeing bent downwardly to reinforce the structure. The arm is off-set at50 and joins a generally U-shaped frame of angular cross sectionincluding one arm 51 whichforms substantially an extension of the armportion 49, a parallel opposite arm 52 and a connecting arm 53. The arms51 and 52 are provided with opposed inwardly directed lugs 54 and 55 andthe connecting member 53 is provided centrally with an aperture 56 towhich one end of a biasing spring may be connected.

The lever which is directly actuated by the operating lever 10 isillustrated in Figure 9 of the drawings. This lever includes anelongated body portion 57 having one pair of laterally projecting ears59 near one extremity thereof and a second pair of laterally extendingears near the other end thereof. An upwardly directed lever arm' 61extends at substantially right angles to the elongated arm 57 and isprovided with a slightly rounded upper extremity 62. An elongatedcentrally located slot 63 extends through much of the length of the arm57 and through much of the length of the angularly extending arm 61,being in the ends of these arms which are joined. An aperture 64 isprovided in the arm 57 spaced from an end of the slot 63, this apertureproviding an anchoring place for a lever biasing spring which will belater described.

opposed fulcrum points for supporting the pivoted levers 4 The controllever 16 and the angular lever 65 illustrated in Figure 9 are assembledwith the lever support 36. The lugs 54 and of the operating lever 113are engaged with one fulcrum point .46 in each of the notches 43. Thelaterally extending lugs or cars of the angular lever are engaged withthe other fulcrum point of each notch 43. A spring 66 is anchoredbetween the aperture 64 of the angular lever 65 and the aperture 56 ofthe control lever 10. Pivotal movement of the angular lever 65 iscontrolled by the engagement of the lugs or ears 59 with projections 67and 69 at one end of each of the side walls 39 and 46 of the switchsupporting frame 36. Pivotal movement of the control lever 19 is limitedby engagement of "the cross member 53 with projections 70 and 71 on theside walls 39 and 40 of the switch supporting frame 36. When the controllever 10 is moved upwardly the angular lever 65 remains inactive untilthe spring 66 directs an upward pull upon the free end of the lever arm57. At this time the angular lever moves into its opposite extremeposition with the lugs 59 engaging the upper projections 69. When thecontrol lever 10 is lowered the angular lever 65 remains stationaryuntil the force of the spring 66 directs a downward pull upon the freeend of the lever arm 57, thus swinging the angular lever 65 until itsprojecting lugs 59 engage the lower projections 67 of the supportingframe 36.

In order to bias the operating lever upwardly, I provide a helicalspring 72 which is connected at one end to the aperture 56 of the crossmember 53. This spring 72 extends upwardly into a tubular sleeve 73extending through the platform 33. The sleeve 73 includes a relativelysmall diameter lower portion 74 and a relatively large diameter portion75, the two portions forming a shoulder therebetween which engagesagainst the upper surface of the platform 33 and prevents the sleevefrom being pulled downwardly. A machine screw 76 or other such threadedelement extends downwardly through the sleeve 73 and is threaded intothe upper end of the spring 72. By rotating the screw 76 in onedirection the spring may be pulled upwardly into the tubular member 73,the internal diameter of this sleeve being such as to prevent Ithespring from slipping off the end of the threaded member. Rotation of thethreaded member in the opposite direction decreases the tension on thespring. The tension is usually sufficient to bias the operating lever 10into position with its outer end or handle end upwardly.

An insulation block 77 cooperates with the up-turned arm 61 of theangular or bell crank lever 65 to form a pair of toggle levers. Theinsulation block 77 extends at least the width of the space contacts tobe engaged' and is provided with an upwardly directed groove 79 in itsundersurface designed to rest upon the rounded upper edge 62 of thelever arm 61. The upper end of the insulation block is provided with acentral upward projection 80 designed to fit between the spaced contactblades engaged and includes spaced grooved portions 81 and 82 onopposite sides of the central projection.

As indicated in Figure 7 of the drawings the spaced contact blades 83and 84 are anchored between locating ribs on the undersurface of theblock or platform 33. The locating ribs 85 project downwardly in spacedA similar pair of downwardly projecting ribs 86 aceommodate the contactblade 84 therebetween and properly locate this blade. Rivets or otherfastening means 87 and 89 connect these blades electrically withterminal plates: 90 and 91 on the upper side of the platform 33 as shownin Figure 3. Screws 92 and 93 extend into the terminal plates 96 and 91to permit the connection of a wire to each plate.

The free ends of the contact blades 83 and 84 support contact points94and 95 respectively. These contact points are engageable with fixedcontact points 96 and 97 (see Figure 6) which are connected by rivets orother fastening means extending through the platform with contact plates99 and 100. These contact plates are also provided with threaded screws101 and 102 by means of which the plates may be connected to aconductor.

In assembling the switch the contact blades with their points attachedare mounted upon the platform 33 so that the contact blades are securedto their respective contact plates and the fixed points are connectedwith their respective terminals. The operating lever 10 and the angularlever 65 are supported upon the switch arm support frame 36 aspreviously described and the springs are attached to these levers. Theframe 36 is attached to the bottom panel 23 of the support 22 and theplatform 33 is sprung between the end walls 24 and 25 of this element.The spring 72 is inserted into the sleeve 73 and anchored in place.During the assembly operation the block 77 is interposed between theupper end 62 of the anchor lever 65 and down-turned ears 103 on theswitch blades 83 and 84. These ears 103 are formed by doubling the endsof the contact blades back upon themselves and bending the extremitiesof the rearwardly bent portions downwardly.

The housing also includes a 'U-shaped body member 104 including a rearwall 105 and parallel side walls 106 and 107. The side walls 106 and 107extend over the side panels 24 and 25 of the support 22 and are securedthereto by screws or other fastening means. The side walls 106 and 107thus hold the side walls 24 and 25 from spreading apart and thus preventthe platform 33 from being disengaged.

This provides a switch housing having an open front and open top. Theremaining two sides are closed by a cover element 109 having a top wall110 and front wall 111. Flanges 112 and 113 (see Figures 2 and 4)telescope marginal portions of the side walls 106 and 107 and :a rearflange 114 lies rearwardly of the upper margin of the rear wall 105 tohold the housing assembled. A securing screw 115 extends through thelower margin of the cover and into the aperture 27 of the flange 26 tohold the structure assembled. Registering notches 116 and 117 in thesupport 22 and the enclosure portion 104 respectively permit theoperating lever 10 to extend through the side of the housing forconnection with the chain 11.

'It will be noted that when the contact points are in electrical contactthe insulation block 77 engages the switch arms between the anchoredends and the point supporting ends so as to exert a force upon thecontact arms. Furthermore, it will be noted that when the contacts areclosed the toggle linkage formed by the block 77 and the lever arm 61 issubstantially aligned so that the spring force of the contact arms cannot exert any material force upon the levers tending to move them totheir other extreme position. In disengaged position of the contactblades, the spring force is released both from the contact blades andthe toggle levers.

In accordance with the patent statutes, I have described the principlesof construction and operation of my switch, and while I have endeavoredto set forth the best embodiment thereof, I desire to have it understoodthat obvious changes may be made within the scope of the followingclaims without departing from the spirit of my invention.

Iclaim:

1. A switch including a strip bent into angular formation, meanshingedly supporting said strip adjacent to the point of bend thereof,means engaging one end of said strip and pivoting the same, meanslimiting pivotal movement of said strip in each direction, a pair ofcontact blades supported in substantially parallel spaced relation, andan insulation block having a groove in one end thereof in which isengaged the other end of said angularly bent strip, said bladesextending at substantially right angles to said other strip end, andmeans pivotally connecting said insulation block to said contact blades,said other end of said angularly bent strip and said insulation blockforming a pair of toggle levers to actuate said contact blades uponpivotal movement of said angular strip, and independent means connectedto said lever for selectively biasing said strip to either extremeposition.

2. The structure described in claim 1 and including projecting meansextending between said spaced contact blades.

3. The construction described in claim 1 and including substantiallyright .angularly extending ears on said contact blades and grooves insaid insulation block on the end thereof opposite the first named grooveto accommodate said ears and to form a pivotal connection therewith.

4. A switch including an operating lever, means pivotally supportingsaid operating lever, an angular lever, means pivotally supporting saidangular lever adjacent the point of bend therein, and spring meansconnecting said operating lever and said angular lever to urge saidlevers toward their respective pivots, resilient means biasing saidoperating lever toward one extreme position, said resilient meansincluding a helical spring connecting to said operating lever, a tubularenclosure into which said spring extends, and a threaded memberthreadably engageable with said helical spring to adjust the tension onsaid spring upon rotation of said threaded member.

5. In a switch frame means, a lever pivotally supported intermediate itsends by said frame means for movement between two extreme positions, apair of spaced contact blades mounted in substantially parallel spacedrelation to the frame means, and an insulating block having a groove inone end thereof designed to accommodate one end of the lever and havingrocking engagement at its other end with said contact blades, said oneend of the lever and said insulation block forming toggle means toactuate said contact blades upon pivotal movement of said lever,independent means connected to said lever for selectively biasing saidlever to either extreme position and including projecting means on saidblock extending between said spaced contact blades.

6. A switch including contact means, an operating lever actuating saidcontact means, a flexible means depending from said operating lever,means of greater density than water supported on said flexible means,said means continuously exerting a downward force on said lever, andmeans for biasing said operating lever upwardly, said means on theflexible means operating upon substantial submersion to reduce theeffective pull upon said flexible means and said biasing means acting toelevate said operating lever.

References Cited in the file of this patent UNITED STATES PATENTS564,283 Hunt July 21, 1896 842,554 Johnson Jan. 29, 1907 1,610,213 VilleDec. 7, 1926 1,924,639 Corcoran Aug. 29, 1933 2,314,995 Lennholm Mar.30, 1943 2,354,282 Shaw July 25, 1944 2,454,185 Kmiecik Nov. 16, 19482,456,112 Dodd Dec. 14, 1948 2,487,374 Riche et al Nov. 8, 19492,548,280 Allan Apr. 10, 1951 2,564,655 Binford Aug. 21, 1951 2,572,622Hollinshead Oct. 23, 1951 2,601,152 Kmiecik June 17, 1952 OTHERREFERENCES Patent Law and Practice (pages 3045), Leon J. Amdur, 1945,Clark Boardman Co., Ltd., New York, N. Y.

